cuajo

Cuajo is a term used in dairy science and gastronomy to designate both the coagulating agent that curdles milk and the solid mass that forms as a result of coagulation. The primary sense in cheese making is the coagulum that becomes curd, which is processed further to produce cheese and other dairy products. The verb related to this process is cuajar, and the noun cuajo refers to the set or curdled mass itself.

Coagulants used to produce cuajo can be of different origins. Animal-derived rennet, containing the enzyme chymosin, is the traditional source and is still used for many classic cheeses. In modern production, microbial rennets produced by fungi or bacteria and plant-based coagulants are common alternatives, especially for vegetarian or halal and kosher cheeses. Plant coagulants include preparations from thistle or cardo, which can influence texture and flavor differently from animal rennet.

The process typically involves heating milk, adding the coagulant, and allowing it to coagulate into a solid curd. The cuajo is then cut, heated, and worked to expel whey and form the final cheese. The type and amount of cuajo, along with processing conditions, affect texture, moisture, and flavor of the cheese.

Variations in usage reflect regional cheese traditions and dietary practices. In Spanish-speaking regions, cuajo is widely understood as both the coagulating agent and the curd formed during cheese making. Etymologically, the term derives from cuajar, meaning to set or coagulate.